Cold shifting problems

[DaGlitch]

I have looked around to no avail. So my problem is this. In the morning after the truck has been sitting overnight i'll go to start it. Starts no problem. Let the motor warm up. Put it into drive and try to go forward. So it will be barely creeping along no matter how much gas i give . Once everything has warmed up some more it shifts perfectly fine. The tranny fluid looks fine. I havn't check the tranny filter and don't know how long it's been since it's been checked. Engine has ~37k miles but i know that really doesn't matter on these vehicles.

I called around town to get some input as to what it may be and many people have said that it sounds like "morning sickness" for the tranny. That the seals inside are hardening up and when the fluid warms up it softens the seals a little bit. It was also consensus that a full rebuild of the tranny is in order. I would really like to avoid this and only have this as a last resort cause $$ is pretty short right now, but i am unsure of what else to check.

Thanks SS!

 

[ralbelt]

I have this same problem. Mine will hesitate for the first two stop and go's after sitting over nite. I have a new filter and fluid and all new vacume lines. It shifts perfectly after two times and all day long no problem. Sometimes dropping into first will speed up the process. I'm just learning to live with it. But i'll be watching this thread for some fresh input.

 

[burbn10]

Try some Lucas Stop-Slip additive. Good stuff. It reconditions seals and helps maintain proper viscosity. I've had 3 transmission guys recommend that stuff even after a fresh rebuild. I've had it in my last 2 trucks and have had no tranny issues.

 

[DaGlitch]

I'll give that stuff a shot and continue to investigate the symptoms. So you're thinking that it's the seals as well i'm guessing? Thanks burbn10.

 

[burbn10]

I'll give that stuff a shot and continue to investigate the symptoms. So you're thinking that it's the seals as well i'm guessing? Thanks burbn10.

Yeah. Those lip seals are made of an early synthetic rubber and petrify over time. Heating them softens them up and makes them seal better like you mentioned before.

 

[Buzz]

I know this is an older post, but did you ever come up with a solution? Mine seems to be a little stubborn shifting when its cold, after it shifts its fine for the rest of the day.

 

[DaGlitch]

Buzz,
Sorry I never updated this post, but it ended up being my seals. They were shot and not holding a seal any more. After replacing them, It worked like a champ. I didn't know this but when the vehicle was shifted into drive, you could hear a faint hissing nose coming from the tranny. This was the indication that my seals were gone. Good luck!

 

[Buzz]

do you know wich seals they were, thanks

 

[DaGlitch]

Mine ended up being the valve body seal. Ended up buying an overhaul kit from monster transmissions and replaced all the seals ( I don't work for them, just found them as a great price). Banner Kit: TH400 Transmission. Hope it helps!

 

[cpf240]

Mine ended up being the valve body seal. Ended up buying an overhaul kit from monster transmissions and replaced all the seals ( I don't work for them, just found them as a great price). Banner Kit: TH400 Transmission. Hope it helps!

Did you do the work yourself? If so, did it require any special tools, and how hard was it? If not, how much was it to have a shop do the work?

I've never worked on transmission internals, manual or automatic, but would like to learn!

No, I'm not hoping my transmission goes out just so I can learn!